Question
Suggest an activity to prepare a magnetic compass by using an iron needle and a bar magnet.
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Answer
Steps involved in preparing a magnetic compass are:
- Take an iron needle which is to be magnetised.
- Magnetise it using a bar magnet.
- Insert the magnetised needle through a small piece of cork.
- Let the cork float in a water in a bowl. Make sure that the needle does not touch the water.
- Your magnetic compass is now ready to work. Note the direction in which the needle points when the cork is floating.
- Rotate the cork, with the needle fixed in it, in different directions. Note the direction in which the needle points when the cork begins to float again without rotating. You will observe that the needle indicates the North-South direction when it comes to rest.
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$COLUMN\ I$
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$COLUMN\ II$
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Activity.
Collect samples of vinegar, lemon juice, mustard oil or coconut oil, kerosene or any other liquid. Take a glass tumbler. Fill it up to half with water. Add a few spoonfuls of one liquid to this and stir it well. Let it stand for five minutes. Observe whether the liquid mixes with water (see figure). Repeat the same with other liquids, as many different liquids as are available to you. Write your observations in Table.
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